linux-kernel - Re: [PATCH] arm:traps: Don't print stack or raw PC/LR values in backtraces

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Date:   Fri, 9 Oct 2020 09:08:50 +0100
From:   Russell King - ARM Linux admin <linux@...linux.org.uk>
To:     Xiaoming Ni <nixiaoming@...wei.com>
Cc:     dima@...sta.com, will@...nel.org, jpoimboe@...hat.com,
        akpm@...ux-foundation.org, christian.brauner@...ntu.com,
        viro@...iv.linux.org.uk, ldufour@...ux.ibm.com, amanieu@...il.com,
        walken@...gle.com, ben.dooks@...ethink.co.uk, tglx@...utronix.de,
        bigeasy@...utronix.de, mingo@...nel.org,
        vincent.whitchurch@...s.com, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org, wangle6@...wei.com,
        luohaizheng@...wei.com
Subject: Re: [PATCH] arm:traps: Don't print stack or raw PC/LR values in
 backtraces

On Fri, Oct 09, 2020 at 03:59:57PM +0800, Xiaoming Ni wrote:
> Printing raw pointer values in backtraces has potential security
> implications and are of questionable value anyway.
> 
> This patch follows x86 and arm64's lead and removes the "Exception stack:"
> dump from kernel backtraces:
> 	commit a25ffd3a6302a6 ("arm64: traps: Don't print stack or raw
> 	 PC/LR values in backtraces")
> 	commit 0ee1dd9f5e7eae ("x86/dumpstack: Remove raw stack dump")
> 	commit bb5e5ce545f203 ("x86/dumpstack: Remove kernel text
> 	 addresses from stack dump")
> 
> Signed-off-by: Xiaoming Ni <nixiaoming@...wei.com>

I am really not happy about this - it hurts at least my ability to
debug the kernel when people post oopses to the mailing list. If
people wish to make the kernel harder to debug, and are prepared
to be told "your kernel is undebuggable" then this patch is fine.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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